The battle for market share is especially intense in Southern California, where Fresh & Easy, Northgate Gonzalez Markets and big-box “super stores” are making inroads against union chains like Ralphs, Vons and Albertsons.

Both chains hope that customers will come in for the reduced costs and spend a larger share of their budget in the store.

“These things tend to catch a wildfire,” said retail expert Garrick Brown. He said it wouldn’t be surprising to see similar announcements of price cuts from Vons (Safeway) and Albertsons.

“Grocery margins are just so tight,” said Brown, national retail research director at Terranomics/ChainLinks in the Sacramento area. “When they go on a price war like this, it’s not just to increase market share and win customers — it’s to hurt their competitor.”

Price wars have happened before, most recently in 2009, when Vons, Ralphs and — to a lesser degree — Albertsons slashed prices as discounters Walmart and Target began selling more food. That effort eventually fizzled out.

Another retail analyst, the “Supermarket Guru” Phil Lempert, has a different perspective: He doesn’t expect there to be a price war this time around.

“While you have these two retailers doing it, I don’t expect a lot of others to do it,” said Lempert, a Santa Monica-based consumer behavior expert. “The idea of everyday low pricing, people have gone back and forth with it for decades. Typically, it doesn’t work from a financial standpoint.”

Lempert believes the lower prices instead signal new efficiencies and streamlining by the chains.

Ralphs, for example, eliminated double coupons. Other stores might cut the number of checkstands and offer self-service checkout. “It’s not going to be about price,” Lempert said. “It’s going to be about stores getting rid of services and getting rid of waste.”

Grocers call this approach “investing in price.” The idea is that lower prices will generate enough customer traffic and loyalty to make up for the short-term sacrifice in profit.

Last month, Kroger-owned Ralphs announced the price reductions on more than 13,000 grocery items at 248 Southern California stores, including 25 in San Diego County. The lost revenue will be made up through changes in purchasing and efficiencies. Ralphs will also no longer double coupons under $1 or issue rewards checks, saying that the prices are lower for everyone now. Stores will still do promotional pricing from week to week on top of the everyday prices.

“Customers are saying: ‘I want lower prices, I want you to make it easier and I want it to be immediate,” said spokeswoman Kendra Doyel. “We took items our customers buy more often or every day, and we lowered those prices throughout the entire store.”

The biggest price drops were in the produce department, which Doyel said is an important zone for Southern California customers.

Walmart hasn’t issued a formal announcement about its price drops but at an industry conference in March, an executive shared the plans to lower prices on food and consumables, saying that consumers would come for the food then fan out to make purchases in other parts of the store.

A spokesman declined to comment further.

Walmart said the price lowering will cost it $1 billion, compared with its $145 billion in grocery sales last year in the U.S.